LPC47M140-NC SMSC [SMSC Corporation], LPC47M140-NC Datasheet - Page 28

• Manufacturer Part Number: LPC47M140-NC
• Description: 128 PIN ENGANCED SUPER I/O CONTROLLER WITH AN LPC INTERFACE AND USB HUB
• Manufacturer: SMSC [SMSC Corporation]

BIT 0 DIRECTION
Active low status indicating the direction of head movement. A logic "0" indicates inward direction; a logic "1"
indicates outward direction.
BIT 1 WRITE PROTECT
Active high status of the WRITE PROTECT disk interface input. A logic "1" indicates that the disk is write protected.
BIT 2 INDEX
Active high status of the INDEX disk interface input.
BIT 3 HEAD SELECT
Active low status of the HDSEL disk interface input. A logic "0" selects side 1 and a logic "1" selects side 0.
BIT 4 TRACK 0
Active high status of the TRK0 disk interface input.
BIT 5 STEP
Active high status of the latched STEP disk interface output pin. This bit is latched with the STEP output going active,
and is cleared with a read from the DIR register, or with a hardware or software reset.
BIT 6 DMA REQUEST
Active high status of the DMA request pending.
BIT 7 INTERRUPT PENDING
Active high bit indicating the state of the Floppy Disk Interrupt.
STATUS REGISTER B (SRB)
Address 3F1 READ ONLY
This register is read-only and monitors the state of several disk interface pins in PS/2 and Model 30 modes. The
SRB can be accessed at any time when in PS/2 mode. In the PC/AT mode the data bus pins D0 - D7 are held in a
high impedance state for a read of address 3F1.
PS/2 Mode
BIT 0 MOTOR ENABLE 0
Active high status of the MTR0 disk interface output pin. This bit is low after a hardware reset and unaffected by a
software reset.
BIT 1 MOTOR ENABLE 1
Active high status of the MTR1 disk interface output pin. This bit is low after a hardware reset and unaffected by a
software reset.
BIT 2 WRITE GATE
Active high status of the WGATE disk interface output.
SMSC DS – LPC47M14X
RESET
RESET
COND.
COND.
PENDING
7
1
1
INT
7
0
6
1
1
DRQ
6
0
DRIVE
SEL0
5
0
STEP
F/F
5
0
TOGGLE
Page 28
WDATA
4
0
TRK0 nHDSEL
N/A
4
TOGGLE
RDATA
3
0
3
1
WGATE
INDX
N/A
2
0
2
MOT
EN1
WP
N/A
1
1
0
nDIR
MOT
EN0
0
1
0
0
Rev. 03/19/2001